Total knee replacement induces peripheral blood lymphocytes apoptosis and it is not prevented by regional anesthesia - a randomized study

ABSTRACT BACKGROUND: Among the many changes caused by a surgical insult one of the least studied is postoperative immunosuppression. This phenomenon is an important cause of infectious complications of surgery such as surgical site infection or hospital acquired pneumonia. One of the mechanisms leading to postoperative immunosuppression is the apoptosis of immunological cells. Anesthesia during surgery is intended to minimize harmful changes and maintain perioperative homeostasis. The aim of the study was evaluation of the effect of the anesthetic technique used for total knee replacement on postoperative peripheral blood lymphocyte apoptosis. METHODS: 34 patients undergoing primary total knee replacement were randomly assigned to two regional anesthetic protocols: spinal anesthesia and combined spinal-epidural anesthesia. 11 patients undergoing total knee replacement under general anesthesia served as control group. Before surgery, immediately after surgery, during first postoperative day and seven days after the surgery venous blood samples were taken and the immunological status of the patient was assessed with the use of flow cytometry, along with lymphocyte apoptosis using fluorescent microscopy. RESULTS: Peripheral blood lymphocyte apoptosis was seen immediately in the postoperative period and was accompanied by a decrease of the number of T cells and B cells. There were no significant differences in the number of apoptotic lymphocytes according to the anesthetic protocol. Changes in the number of T CD3/8 cells and the number of apoptotic lymphocytes were seen on the seventh day after surgery. CONCLUSION: Peripheral blood lymphocyte apoptosis is an early event in the postoperative period that lasts up to seven days and is not affected by the choice of the anesthetic technique